I have changed from iPhone 8 Plus to iPhone 13 mini. In Zoom my thumbnail to right shows image flipped and with black bars tope. This is annoying as I use Zoom for Pilates class and need to see what the teacher is seeing at her end, but black bars stop me doing this. Also I connect my iPhone to Apple TV box, but the image on my TV is now a smaller frame not full screen of TV.
All worked fine with iPhone 8. Why would it be different on another iPhone.
I believe it is due to the iphone 8 plus having a 1080p (1920 x 1080) 16:9 screen, while iPhone 13 mini although it has a bigger screen at 2340 x 1080, its screen ratio is 19.5:9. As most web cameras output at 4:3 or 16:9, it is normal to see black bars if your screen is using a different format.
This is not easily fixed, but there 3 ways you can try:
1. On the Zoom app video settings, please check the aspect ratio and try with original ratio:
Aspect Ratio: Select an aspect ratio when viewing participants' video. This setting doesn't affect your own video.
Scale to fit: Participants' video will be scaled to fit your phone's screen, causing video to be cropped.
Original ratio: Participants' video will be shown in their original aspect ratio. In other words, the aspect ratio of their video will be the same as what's displayed in the desktop client.